Question

Why at cold temperature growth of plant increases vernilisation?

Answer 1

Vernalization is the acceleration of development by exposing sensitive cultivars to cool temperature during the early stages of crop ontogeny. The plant apex may sense vernalizing temperatures from seed imbibition, throughout the vegetative phase. Vernalization requirements are typical of crops with a temperate origin. In many of these crops, there are ‘winter’ and ‘spring’ cultivars. It is frequently assumed that vernalizationrequirements are characteristic of winter genotypes within a particular species. The difference between spring and winter types may be restricted, however, to the magnitude of vernalization responsiveness (e.g. Levy and Peterson, 1972; Slafer and Rawson, 1994a).

Vernalization may be reversed if the period of low temperature is interrupted, an effect known as ‘devernalization’. This was experimentally proven in wheat by Gregory and Purvis (1948) and Purvis and Gregory (1952). Dubert et al. (1992) showed that devernalization may occur at temperatures between 20 and 30°C.

Excluding the effects of temperature per se by the calculation of the length of the phases in degree days, photoperiod and vernalization are generally considered to account for most of the differences in development rate among cultivars; any ‘residual’ difference after the vernalization and photoperiod requirements were satisfied would be the consequence of differences in ‘basic development rate’ or ‘intrinsic earliness’ (Major, 1980; Flood and Halloran, 1984; Masle et al., 1989, Slafer, 1996), which are discussed in section 4.1.3

Answer 2

At cold temperature vernalization accelerates the growth of plants by increasing the resistance of plants to fungal effect.

Explanation:

• Vernalization is a process which at low temperature increase the growth and yield of plants, decreases fungal effect and make the plant to flower earlier.

• Vernalization occurs in two ways, namely facultative and obligate. If seedling is done at low temperature then facultative vernalization results in early flowering .

• The plants need a cold environment for better germination and flowering. Vernalization makes the plants more adaptable by allowing them to grow in regions where they usually don’t grow.